Hello! 
My dad has given me floor plans in blueprint paper and he wants me to draw / copy them in AutoCAD. 
I've have learnt here that you should always draw 1:1 in model space and adjust the scale later on in paper space. 
  
My problem is that the floor plans are printed in a scale of 1:75 meters. 
 - so how should I draw / copy them (use a ruler? ) 
 - and what units will I use to draw the lines?